Abstract

Despite its demonstrated effectiveness, colorectal cancer (CRC) testing is suboptimal, particularly in vulnerable populations such as those who are publicly insured. Prior studies provide an incomplete picture of the importance of the intersection of multilevel factors affecting CRC testing across heterogeneous geographic regions where vulnerable populations live. We examined CRC testing across regions of North Carolina by using population-based Medicare and Medicaid claims data from disabled individuals who turned 50 years of age during 2003-2008. We estimated multilevel models to examine predictors of CRC testing, including distance to the nearest endoscopy facility, county-level endoscopy procedural rates, and demographic and community contextual factors. Less than 50% of eligible individuals had evidence of CRC testing; men, African-Americans, Medicaid beneficiaries, and those living furthest away from endoscopy facilities had significantly lower odds of CRC testing, with significant regional variation. These results can help prioritize intervention strategies to improve CRC testing among publicly insured, disabled populations.

County-specific location of endoscopy facilities, endoscopy procedural rates, density of Medicare and Medicaid beneficiaries, and major urban cities in North Carolina. Notes: this map was generated by using 2007 data from the State Medical Facilities Plan (SMFP) about the location and endoscopy procedural rates throughout North Carolina. The total number of endoscopy centers in each county is indicated in the center of each county. County level endoscopy procedural rates ranged from 0 to 1462 endoscopies performed annually per 10,000 residents, where darker shading reflects fewer endoscopy procedures performed at the county level and lighter shading reflects more endoscopy procedures performed at the county level. The color of shading (i.e., red, orange, yellow) indicates the density of the study population (i.e., publicly insured 50-year-olds) as a function of the general population (per 10,000 residents) living in the county, where red indicates greater density of publicly insured individuals and yellow indicates lower density of publicly insured individuals. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Multivariable-adjusted predicted probabilities of colorectal cancer testing by county. Panel a: total sample (all insurance providers). Panel b: Medicaid-only sample, Panel c: Medicare-only sample, and Panel d: dually insured by Medicaid and Medicare sample. Notes: these maps depict multivariable-adjusted regional variation by county in individual colorectal cancer testing during a 6-year period among people turning 50 years of age who were publicly insured during 2003–2008 (panel a: all providers; panel b: Medicaid only; panel c: Medicare only; and panel d: dually insured by Medicaid and Medicare). Shading reflects county-specific predicted probabilities in tertiles, as generated from multivariable models. Predicted probabilities were calculated by averaging the individual predicted probabilities from the final model for each county. Increasingly darker red shading indicates lower levels of CRC testing across the state, whereas increasingly lighter pink shading indicates higher levels of CRC testing across the state, controlling for all other person-level and county level factors. Major urban cities (more than 100,000 persons) are designated by callouts, and numbers indicate the count of endoscopy centers in each county. In panel 3b, the lack of any eligible beneficiaries in the 5-county Piedmont area consisting of Cabarrus, Davidson, Rowan, Stanley, and Union (shaded in gray) is indicative of a special, prepaid managed care plan operating in the Piedmont Behavioral Healthcare catchment area during the study period. As such, we excluded Medicaid-only beneficiaries in this region due to special program features operating in that region. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)